A new program to test wastewater for substances like fentanyl, methamphetamine and cocaine is giving San Francisco’s health officials a new window into the city’s pressing overdose crisis.
The effort comes as San Francisco recently experienced the worst year for overdose deaths on record in 2023, when 806 people died of accidental overdose.
“For the first time, we have data that can shed light on the amounts of drugs that are being used in the city here,” said Jeffrey Hom, director of population behavioral health for the San Francisco Department of Public Health. “This is something that we haven’t had before. So much of the data that we look at within the health department is based on individuals who are receiving a certain service or who have experienced a certain outcome, like a nonfatal overdose.”
San Francisco health officials started tracking drug use and supply trends in November 2023 to monitor the presence of different drugs and to also check for changes in the illicit drug supply.
Wastewater samples are collected every two weeks from two different locations, one on the city’s west side and another on the east side. Currently, the city is checking for fentanyl, cocaine and methamphetamine, as well as all three substances in their metabolized form. The samples are then sent to a lab where they are analyzed, and the results are shared back with the city.
Early results from the first four months of testing show there were often higher concentrations of drugs, including fentanyl, cocaine and methamphetamine on the east side of the city compared with the west. That largely tracks with geographic data from the Office of the Chief Medical Examiner, which releases monthly reports on overdoses in the city.
Fentanyl, a potent opioid about 50 times stronger than heroin, has contributed to the majority of recent overdose deaths in San Francisco.
However, the wastewater data showed much higher concentrations of stimulants across the city. For example, there were 1552 milligrams of methamphetamine per 1000 people per day found in samples collected on the east side of the city on March 7, 2024, compared to 34 milligrams of fentanyl.
That doesn’t necessarily mean there are more people using stimulants, however. The body metabolizes each substance differently, making it hard to compare the prevalence of individual substances. Instead, Hom said, the city is using the findings to monitor changes in the drug supply and use trends over time.
“We’re not able to directly compare those and make an assumption that many more people or that much more stimulants are being used because of the way these drugs are metabolized in the body. So trying to make the comparison between drugs is difficult,” Hom said.
Public health officials say they hope to use the data to advise the public on overdose risk and drug supply trends.
The effort is part of a study funded by the National Institute on Drug Abuse, which ends in August, that San Francisco and other local municipalities are participating in. But the city’s health officials say they hope to expand and continue the program after the study wraps up.
San Francisco previously used wastewater testing during the COVID-19 pandemic to track the rise and fall of the virus on a population level. However, the city is not alone in its endeavor to use the technology for the overdose crisis as well. Marin County started using the approach in July 2023. Public health officials there issued a health advisory about an increase in fentanyl overdoses that aligned with the wastewater testing, which showed higher rates and amounts of fentanyl in the same period.
“Much of the potential for this kind of surveillance revolves around the opportunity to identify new drugs or something that’s just starting to make its way into the drug supply here,” Hom said. “I am hopeful as we look to the next iteration of this that we not only increase the frequency of testing, but increase the number of drugs and especially novel drugs so our response can be timely and focused.”
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